1. Field of the Invention
This invention relates to a memory which is used in an information processing apparatus such as a computer system and a method for storing code/data in the memory. Particularly, this invention relates to a memory which is accessed by a processor of a successive type effecting grey code addressing and method for storing code/data in such memory. More particularly, this invention relates to a memory which allows code or data to be read out in the same sequence as it was originally stored even when a processor of a successive type successively accesses to the memory based on an address of a grey code system, and a method for storing code/data in such memory.
2. Prior Art
Along with recent technological revolution, various kinds of computer systems including host/main frame computers, workstations and personal computers for consumers have been developed, manufactured and widely spread.
The basic components of such computer system includes a processor executing predetermined processing and a memory which the processor utilizes. Specifically, the processor is locally provided with a memory in itself, temporarily stores in the memory program codes which the processor executes and execution data and accesses to the memory at each processing step to read out a code from or write execution data into the memory. The processor and the memory are usually connected by a memory bus on which the processor sends an address to specify an access location in the memory.
However, the memory resource of a computer system is typically limited because the price per unit of storage capacity of a memory is relatively expensive. Thus, the computer system is provided with a storage of a large capacity and of a relatively inexpensive unit price, such as a hard disk, and code/data are exchanged or swapped between the memory and the disk as appropriate.
There may be a variety of schemes of addressing to allocate code or data in a memory space. In the area of the current computer science, a binary code system is most popular in which addresses in ascending decimal order are represented by binary numbers in the same order.
On the other hand, most of processors used in computer systems in these days are of a successive execution type in which addresses for accessing to the memory are consecutive. In other words, the program codes executed by the processor are normally described according to the sequence of execution and the processor can obtain the codes according to the sequence in a source program by successively generating addresses in ascending order, for example. An address generator provided in a processor chip is adapted to generate addresses, for example.
However, it has been pointed out that a problem of bit transition exists when addresses are outputted in the order in the source program to the memory space which is represented by binary codes. As mentioned in the above, a binary code is a simple binary representation of each numeric value (address value) in the order of a decimal number and there is no consideration of bit transition.